At the outbreak of Civil War, regiments stationed along the Oregon Trail are posted back East to fight for the Union. Hastily assembled militia units seize control of the trail forts and wagon-trains are left vulnerable to exploitation and attack. Halted with a broken axle, westbound pioneers Eve Maddison and Wesley Jackson encounter a mysterious frontiersman known simply as 'Stranger'. They also run up against the vicious Viperine brothers, in charge of a local militia and plotting to extort money from the stranded pioneers. Stranger insists that everyone is judged by their actions on the trail. His philosophy of courage and self-reliance inspires Eve and Wesley to make a stand against the Viperines - and face up to some difficult truths...